Out of the estimated 847,000 Americans who have hepatitis B virus (HBV), about half are Asian, aidsmap reports. Publishing their findings in the journal Hepatology, researchers analyzed hep B prevalence estimates in non-instutionalized people age 6 and older, according to the National Health and Nutrition Examination Survey (NHANES).
The researchers looked at three periods: 1988 to 1994, which included 21,260 people, 1999 to 2008 (29,828 people), and 2007 to 2012 (22,358 people). To compensate for the small numbers of Asians in the population, the researchers oversampled this demographic starting during 2011 to 2012.
During 1988 to 1994, 5.3 percent of the individuals tested positive for anti-HBc, which indicates a present or past hep B infection. This figure dropped to 4.8 percent during 1999 to 2006 and to 3.9 percent during 2007 to 2012. The researchers used these figures to estimate that a respective 12.1 million, 12.5 million and 10.8 million non-institutionalized U.S. residents had ever had hep B during the three periods.
The prevalence of chronic hep B remained relatively constant throughout the study period: an unadjusted estimate of about 0.3 percent. Thanks to the hep B vaccine, the prevalence of chronic infection dropped among those younger than 20, from 0.2 percent during 1988 to 1994 to 0.03 percent during 2007 to 2012.
Hep B prevalence was 2- to 3-fold higher than the overall population, while the prevalence among Asians, at 3.1 percent during 2011 to 2012, was 10 times greater than the overall population.
The researchers concluded that there were 847,000 people with chronic hep B during 2011 to 2012, and that about 400,000 of these individuals were Asian.
The adjusted prevalence of those who had immunity to hep B thanks to the vaccine rose from 21.7 percent during 1999 to 2006 to 25.1 percent during 2007 to 2012, a 16 percent increase. The researchers estimated that these figures mean that the number of U.S. residents protected by the vaccine increased from 57.8 million to 68.5 million between these two periods.
To read the aidsmap article, click here.
To read the study abstract, click here.